Real-time video communication applications over an Internet Protocol (IP) network, such as online video conferencing and video chatting, are becoming widely deployed nowadays in both enterprise and consumer markets, and will become more and more popular in the foreseeable future. In those applications, the compressed video bitstreams are generally packetized into packets that are smaller than a Maximum Data Unit (MDU) of the underlying IP networks. Packetization schemes are defined under different transportation protocols such as the well-known Real Time Protocol (RTP). To combat the packet losses over the network, Forward Error Correction (FEC) schemes are often applied across the video data packets. The generated error correction packets help to recover the lost video data packets if the number of the lost packets is smaller than the correction capability of the FEC code applied.
For low-delay video communications, only video data that is within a very short period of time, usually data belonging to the same video frame, can be combined into one block of source packets for FEC. The number of video source packets in such cases is usually fairly small, especially for packets of Standard Definition (SD) video resolution and below, and the FEC code correspondingly applied to those video source packets is usually a set of shorter codes (truncated from longer codes). The FEC codes are a large overhead cost, in terms of bandwidth and processing, especially where the number of video source packets is small. Notably, also, the behavior of such shorter FEC codes can vary greatly for different packet loss rates on the communication channel.